Polyimide composed of 3,3′,4,4′-biphenyltetracarboxylic dianhydride (hereinafter may also be abbreviated as s-BPDA) and paraphenylenediamine (hereinafter may also be abbreviated as PPD), which is described, for example, in Patent Document 1, is used in various applications because of excellent heat resistance and mechanical properties.
Further, in Patent Document 2, a method for producing polyimide having excellent heat resistance and mechanical properties composed of pyromellitic dianhydride (hereinafter may also be abbreviated as PMDA) and PPD is described.                Patent Document 1: JP 55-7805A        Patent Document 2: JP 2003-64196A        